112 A YEAR IN SCIENCE 



Water, as you have learned, contracts upon cooling 

 until 4C. (39F.) is reached, then it begins to expand. 

 One hundred cubic feet of water, as ice, will require 

 one hundred and nine cubic feet of space. Thus as 

 water freezes a layer of ice spreads over the surface of 

 the water, Avhile the life underneath continues un- 

 molested. 



The expansive force of freezing water will be under- 

 stood if you will recall what happens to the pipes when 

 the water in them freezes. The freezing water expands, 

 and as the pipe does not expand and the ice must have 

 more room, the pipe bursts. 



Perhaps you have noticed the " fluffed up" appear- 

 ance of the garden soil in the spring just before the 

 frost has gone out of it. During the fall and winter, 

 the water from rains and snow trickled down into the 

 earth and later froze. Ice requires about one-eleventh 

 more space than liquid water, and as the water in the 

 crevices and cracks in the soil froze it required more 

 room. The pressure thus exerted pushed up the sur- 

 face soil, giving it the fluffy appearance. This is a 

 great boon to the farmer, as it helps to pulverize the soil. 

 On rocky hills and mountain sides, this form of weath- 

 ering is making neiv soil by splitting off particles of 

 rock, which are carried to the base of the mountain 

 with each rain. 



Another great use of water is its power of solution. 

 If a spoonful of sugar is placed in a glass of water, the 

 sugar disappears. It has been dissolved by the water. 



